Typical prior art filtration manifolds are employed in filtration systems of the type described above. These filtration systems generally include elongate tubular cartridges enclosing a bundle of the hollow fibre membranes. Manifold or header arrangements are used to connect the cartridges, usually at one or both ends, these manifolds acting to separate and divert the respective flows of the contaminated feed filtrate and cleaning fluid through the system. In this regard, cross-flow systems typically have two feed manifolds (inlet and re-circulation outlet) and one or two filtrate manifolds. In cross-flow filtration systems of the prior art the feed stream to be filtered flows tangential to or across the surface of the membrane. This generates a sweeping action at the membrane surface, keeping the surface cleaner. Conversely, systems configured for dead end operations utilise only one feed inlet manifold and one filtrate outlet manifold during filtration mode. Further, these prior art manifolds or header arrangements are often configured to facilitate the construction of modular two or three dimensional cartridge arrays.
Most typically, the prior art filtration systems, as previously described, are closed to the atmosphere. In such systems, fluid to be filtered, hereinafter referred to as feed, is fed under positive pressure to the filters. In order for this type of system to operate effectively, the elongate tubular filtration cartridges are encased in pressure tight housings. Such housings are then connected to a manifold system which both separates the feed from the filtrate and supports the pressure tight housing. The manifold system may also serve to introduce cleaning fluid to the filtration system.
Prior art filtration systems, as previously described, may also be open to the atmosphere. Typically in such systems, feed is drawn through the membranes under negative pressure. This is achieved by applying a negative, or suction, pressure on the filtrate side of the membrane. Such systems tend to employ less infrastructure and capital works compared with systems closed to the atmosphere as they do not require components that are able to contain relatively higher pressures. For example, there is no need to encase filtration cartridges in individual pressure tight housings in systems open to atmosphere. Typically in these systems, the filtration cartridges are merely substantially immersed in an open tank containing the feed. In such systems it is desirable that an appropriate manifold be provided to both support the filter cartridges and to allow the filtrate to be drawn from the filter while separating the feed from the filtrate. Similarly, as with closed systems, such a manifold may also serve the purpose of supporting a cleaning fluid system.
Prior art filtration systems and their associated filtration cartridges referred to above are often a complex configuration of pipes and parts which are difficult and time consuming to assemble. Further more, the actual manifold system components of the prior art filtration systems are often a complex assembly of parts in themselves.
The prior art filtration systems described above also require regular testing to assess system integrity. Non-integrity may be due to failure of individual filtration membrane hollow fibres, ‘o’-rings or other system components. Integrity testing often requires the removal of either individual system components or filtration cartridges. This removal is often difficult in typical prior art filtration manifolds. Furthermore, as previously discussed, typical prior art filtration manifolds may contain many complex parts. It then follows that integrity testing of these parts can also be time consuming.
It is an object of the present invention to provide a filtration manifold system of the kind herein described which overcomes or ameliorates at least some of the deficiencies of the prior art or at least offers a useful alternative thereto.